I don't think you have to change anything. It's absolutely the same thing on both the Tabby and the DS 12, where you put the weight is of great importance and it takes a good part of skill to make the cat go fast. So may the best sailor, not the best boat win the race.
Have since found out that Bill's son is only 36kg, so its no wonder its riding high. On the plus side even though there was little wind this past weekend, we found out that a 36kg kid can right the boat by themselves which is always good :-)
Hopefully the forecast 15-20 knots for this coming weekend will arrive and we can have some fun pushing the boats a bit :-)